1. Field of the Invention
The present invention relates to a starter having an intermediate gear that is engaged with a ring gear of an internal combustion engine in a cranking operation.
2. Description of Related Art
An example of a starter having an intermediate gear is disclosed in JP-B2-2555492. In this starter, an intermediate shaft is disposed in parallel to an output shaft supporting a pinion gear thereon. An intermediate gear always engaging with the pinion gear is rotatably supported by the intermediate shaft. The pinion gear and the intermediate gear are coupled by a coupler member so that the intermediate gear shifts in its axial direction in accordance with an axial movement of the pinion gear. In a cranking operation, the intermediate gear is shifted toward a ring gear of an internal combustion engine, and a rotational torque of the pinion gear is transmitted to the ring gear via the intermediate gear.
The coupler member is coupled with the intermediate gear with a certain clearance in the axial direction in order to allow rotation of the intermediate gear relative to the coupler member while maintaining engagement with the pinion gear. Therefore, there is a problem that the intermediate gear vibrantly moves in its axial direction due to vibrations of the engine when the starter is not in operation. Such vibrant movement of the intermediate gear generates chattering noises and abrasion between the intermediate gear and the coupler member.